What is the proper administration protocol for universal snake antivenom (antivenin) after a snake bite?

Administration Protocol for Universal Snake Antivenom After Snake Bite

The most effective administration of universal snake antivenom requires immediate transport to a medical facility where the antivenom can be administered intravenously, as this is the only definitive treatment for venomous snakebites. 1

First Aid Measures Before Antivenom Administration

• Activate emergency medical services immediately for any person bitten by a venomous or possibly venomous snake 1
• Rest and immobilize the bitten extremity to reduce systemic absorption of venom 1
• Remove rings and other constricting objects from the bitten extremity to prevent damage from swelling 1
• Apply a pressure immobilization bandage with pressure between 40-70 mm Hg in upper extremities and 55-70 mm Hg in lower extremities around the entire bitten limb to slow venom dissemination by reducing lymph flow 2
• For practical purposes, the pressure is sufficient if the bandage is comfortably tight and snug but allows a finger to be slipped under it 2

Harmful Practices to Avoid

• Do NOT apply suction as first aid for snakebites - it removes very little venom, has no clinical benefit, and may aggravate the injury 2, 1
• Do NOT apply ice to a snakebite wound as it may cause tissue injury 1
• Do NOT use electric shock as it is ineffective and potentially harmful 1
• Do NOT apply tourniquets as they can worsen local tissue injury 1

Antivenom Administration Protocol

1. Initial Assessment:

   • Confirm signs of envenomation (progressive swelling, ecchymosis, coagulation abnormalities, or systemic effects) 3
   • Early administration of antivenom is critical as it prevents irreversible venom-mediated effects 4

2. Preparation:

   • Ensure airway management and ventilatory support if needed 5
   • Establish intravenous access 1
   • Have emergency medications ready to treat potential allergic reactions 6

3. Dosing:

   • For common krait bites (primarily neurotoxic), the recommended initial dose is 10 vials of antivenom 5
   • For other snake species, dosing may vary based on severity of envenomation and specific antivenom used 3

4. Administration Method:

   • Administer antivenom intravenously as the most effective route 3
   • Monitor closely for adverse reactions during administration 5

5. Monitoring and Additional Doses:

   • Continue monitoring for progression of symptoms 4
   • Additional doses may be required as some antivenoms (particularly Fab fragments) have shorter half-lives than IgG molecules and may allow recurrence of venom effects 3

Management of Antivenom Adverse Reactions

• Both acute (anaphylactic or pyrogenic) and delayed (serum sickness type) reactions can occur 6
• Acute reactions usually develop within an hour of antivenom exposure 6
• Serum sickness typically occurs 5-14 days after administration 6
• If allergic reactions occur, stop antivenom treatment promptly and provide immediate anti-allergy treatment 7
• Patients receiving a second treatment of antivenom may develop IgE-mediated immediate hypersensitivity 7

Special Considerations

• The type of snake venom affects treatment approach - neurotoxic venoms (like elapids) vs. cytotoxic venoms (like most North American pit vipers) 1
• Pressure immobilization techniques may be more beneficial for neurotoxic snake bites than for cytotoxic snake bites 1
• Some patients may require very high doses of antivenom for reversal of neurological manifestations, particularly with krait bites 8

Common Pitfalls to Avoid

• Delaying transport to a medical facility to attempt ineffective first aid measures 1
• Failing to remove constricting items like rings, which can lead to ischemic injury as swelling progresses 1
• Excessive movement of the victim, which can increase venom absorption through the lymphatic system 1
• Using pressure immobilization techniques developed for neurotoxic snakes on cytotoxic snake bites 1